An Organic Light Emitting Diode (OLED), as a current type light emitting device, has been widely used in high performance display field due to its advantages of self-luminous, fast response, wide viewing angle and being formable on a flexible substrate. According to a driving mode, the OLED may be classified into a passive matrix driving OLED (PMOLED) and an active matrix driving OLED (AMOLED). The AMOLED display is expected to become a next generation of flat panel display to replace an LCD (Liquid Crystal Display) due to its low manufacturing cost, high response speed, low power consumption, DC driving available for portable devices and wide operating temperature range.
In an existing OLED pixel, a driving transistor is usually made of semiconductor material such as amorphous silicon, polysilicon or metal oxide. However, limited by the manufacturing process, electrical parameters such as the threshold voltage Vth and the mobility K and the like of each driving transistor DT of the OLED pixel frequently fluctuate, thus causing that a current flowing through the OLED device changes with fluctuation of the threshold voltage Vth and the mobility K of the driving transistor DT, resulting in uneven luminance and affecting the display image quality.
It should be noted that, information disclosed in the above background portion is provided only for better understanding of the background of the present disclosure, and thus it may contain information that does not form the prior art known by those ordinary skilled in the art.